Experimental correlation between metallographic evaluation and electrochemical noise in intergranular corrosion tests of aluminium alloys

Abstract

In the present work, the correlation between the metallographic evaluation and electrochemical noise (EN) in intergranular corrosion (IGC) tests of aluminium alloy 2024-T3 has been analysed. For this purpose, the influence of temperature and hydrogen peroxide concentration on the IGC attack has been studied. Similar IGC was observed between 20 and 40 C, showing a low dependence with temperature (at least in this range). Hydrogen peroxide was seen to have a strong effect, leading to IGC activation when raising its concentration. The results of the detailed metallographic evaluation of the samples after the tests were analysed together with the EN measured during the tests. The averaged noise resistance was inversely proportional to the depths of the attacks, whereas the average of the parameter so-called 'Statistical Noise Power' was directly related to the IGC degree. The metallographic evaluation and the EN showed a reasonable experimental correlation. Copyright